1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
|
#include "../libnetdata.h"
#include "arrayalloc.h"
#ifdef NETDATA_TRACE_ALLOCATIONS
#define TRACE_ALLOCATIONS_FUNCTION_DEFINITION_PARAMS , const char *file, const char *function, size_t line
#define TRACE_ALLOCATIONS_FUNCTION_CALL_PARAMS , file, function, line
#else
#define TRACE_ALLOCATIONS_FUNCTION_DEFINITION_PARAMS
#define TRACE_ALLOCATIONS_FUNCTION_CALL_PARAMS
#endif
// max file size
#define ARAL_MAX_PAGE_SIZE_MMAP (1*1024*1024*1024)
// max malloc size
// optimal at current versions of libc is up to 256k
// ideal to have the same overhead as libc is 4k
#define ARAL_MAX_PAGE_SIZE_MALLOC (64*1024)
typedef struct arrayalloc_free {
size_t size;
struct arrayalloc_page *page;
struct arrayalloc_free *next;
} ARAL_FREE;
typedef struct arrayalloc_page {
const char *filename;
size_t size; // the total size of the page
size_t used_elements; // the total number of used elements on this page
uint8_t *data;
ARAL_FREE *free_list;
struct arrayalloc_page *prev; // the prev page on the list
struct arrayalloc_page *next; // the next page on the list
} ARAL_PAGE;
#define ARAL_NATURAL_ALIGNMENT (sizeof(uintptr_t) * 2)
static inline size_t natural_alignment(size_t size, size_t alignment) {
if(unlikely(size % alignment))
size = size + alignment - (size % alignment);
return size;
}
static void arrayalloc_delete_leftover_files(const char *path, const char *required_prefix) {
DIR *dir = opendir(path);
if(!dir) return;
char full_path[FILENAME_MAX + 1];
size_t len = strlen(required_prefix);
struct dirent *de = NULL;
while((de = readdir(dir))) {
if(de->d_type == DT_DIR)
continue;
if(strncmp(de->d_name, required_prefix, len) != 0)
continue;
snprintfz(full_path, FILENAME_MAX, "%s/%s", path, de->d_name);
info("ARRAYALLOC: removing left-over file '%s'", full_path);
if(unlikely(unlink(full_path) == -1))
error("Cannot delete file '%s'", full_path);
}
closedir(dir);
}
// ----------------------------------------------------------------------------
// arrayalloc_init()
static void arrayalloc_init(ARAL *ar) {
static netdata_mutex_t mutex = NETDATA_MUTEX_INITIALIZER;
netdata_mutex_lock(&mutex);
if(!ar->internal.initialized) {
netdata_spinlock_init(&ar->internal.spinlock);
long int page_size = sysconf(_SC_PAGE_SIZE);
if (unlikely(page_size == -1))
ar->internal.natural_page_size = 4096;
else
ar->internal.natural_page_size = page_size;
// we need to add a page pointer after the element
// so, first align the element size to the pointer size
ar->internal.element_size = natural_alignment(ar->requested_element_size, sizeof(uintptr_t));
// then add the size of a pointer to it
ar->internal.element_size += sizeof(uintptr_t);
// make sure it is at least what we need for an ARAL_FREE slot
if (ar->internal.element_size < sizeof(ARAL_FREE))
ar->internal.element_size = sizeof(ARAL_FREE);
// and finally align it to the natural alignment
ar->internal.element_size = natural_alignment(ar->internal.element_size, ARAL_NATURAL_ALIGNMENT);
// we write the page pointer just after each element
ar->internal.page_ptr_offset = ar->internal.element_size - sizeof(uintptr_t);
if(ar->requested_element_size + sizeof(uintptr_t) > ar->internal.element_size)
fatal("ARRAYALLOC: failed to calculate properly page_ptr_offset: element size %zu, sizeof(uintptr_t) %zu, natural alignment %zu, final element size %zu, page_ptr_offset %zu",
ar->requested_element_size, sizeof(uintptr_t), ARAL_NATURAL_ALIGNMENT, ar->internal.element_size, ar->internal.page_ptr_offset);
//info("ARRAYALLOC: element size %zu, sizeof(uintptr_t) %zu, natural alignment %zu, final element size %zu, page_ptr_offset %zu",
// ar->element_size, sizeof(uintptr_t), ARAL_NATURAL_ALIGNMENT, ar->internal.element_size, ar->internal.page_ptr_offset);
if (ar->initial_elements < 10)
ar->initial_elements = 10;
ar->internal.mmap = (ar->use_mmap && ar->cache_dir && *ar->cache_dir) ? true : false;
ar->internal.max_alloc_size = ar->internal.mmap ? ARAL_MAX_PAGE_SIZE_MMAP : ARAL_MAX_PAGE_SIZE_MALLOC;
if(ar->internal.max_alloc_size % ar->internal.natural_page_size)
ar->internal.max_alloc_size += ar->internal.natural_page_size - (ar->internal.max_alloc_size % ar->internal.natural_page_size) ;
if(ar->internal.max_alloc_size % ar->internal.element_size)
ar->internal.max_alloc_size -= ar->internal.max_alloc_size % ar->internal.element_size;
ar->internal.pages = NULL;
ar->internal.allocation_multiplier = 1;
ar->internal.file_number = 0;
if(ar->internal.mmap) {
char directory_name[FILENAME_MAX + 1];
snprintfz(directory_name, FILENAME_MAX, "%s/array_alloc.mmap", *ar->cache_dir);
int r = mkdir(directory_name, 0775);
if (r != 0 && errno != EEXIST)
fatal("Cannot create directory '%s'", directory_name);
char filename[FILENAME_MAX + 1];
snprintfz(filename, FILENAME_MAX, "%s.", ar->filename);
arrayalloc_delete_leftover_files(directory_name, filename);
}
ar->internal.initialized = true;
}
netdata_mutex_unlock(&mutex);
}
// ----------------------------------------------------------------------------
// check a free slot
#ifdef NETDATA_INTERNAL_CHECKS
static inline void arrayalloc_free_validate_internal_check(ARAL *ar, ARAL_FREE *fr) {
if(unlikely(fr->size < ar->internal.element_size))
fatal("ARRAYALLOC: free item of size %zu, less than the expected element size %zu", fr->size, ar->internal.element_size);
if(unlikely(fr->size % ar->internal.element_size))
fatal("ARRAYALLOC: free item of size %zu is not multiple to element size %zu", fr->size, ar->internal.element_size);
}
#else
#define arrayalloc_free_validate_internal_check(ar, fr) debug_dummy()
#endif
// ----------------------------------------------------------------------------
// find the page a pointer belongs to
#ifdef NETDATA_INTERNAL_CHECKS
static inline ARAL_PAGE *find_page_with_allocation_internal_check(ARAL *ar, void *ptr) {
uintptr_t seeking = (uintptr_t)ptr;
ARAL_PAGE *page;
for(page = ar->internal.pages; page ; page = page->next) {
if(unlikely(seeking >= (uintptr_t)page->data && seeking < (uintptr_t)page->data + page->size))
break;
}
return page;
}
#endif
// ----------------------------------------------------------------------------
// find a page with a free slot (there shouldn't be any)
#ifdef NETDATA_ARRAYALLOC_INTERNAL_CHECKS
static inline ARAL_PAGE *find_page_with_free_slots_internal_check(ARAL *ar) {
ARAL_PAGE *page;
for(page = ar->internal.pages; page ; page = page->next) {
if(page->free_list)
break;
internal_fatal(page->size - page->used_elements * ar
|